The invention relates to a method for producing downshift signals for an automatic transmission via a pedal device with at least one pedal element that moves about at least one pivot point and includes at least one motion sensor element.
The invention also relates to a gas pedal device with at least one gas pedal element that may move about a gas pedal pivot point with respect to a surface element, with a motion sensor element that produces a movement characteristic curve, and a downshift-sensor element, whereby the motion sensor element and the downshift sensor device may be moved at least by movement of the gas pedal element, and also a downshift sensor device to perform the method.
A gas pedal device, known from the German Patent No. DE 195 03 335, includes a gas pedal element at whose pivot point is positioned a motion sensor element. A sensor or switch is assigned to the gas pedal element that is controlled by an actuation lever element that can create a downshift signal if necessary.
However, it is not indicated in this reference how the sensor or switch is constructed, or how the signal is created and transmitted.
Downshift switches, also called xe2x80x9ckickdown switchesxe2x80x9d, are known in which a spring-loaded, tap-shaped pushrod body is pressed via a recess with spring-tensioned spheres. However, the downshift force characteristic curve may be altered only by the shape of the tap, the number and size of spheres, and the spring force of the spheres. Also, as a rule, the strike point of the pushrod body is the signal triggering point to control an automatic transmission. A further disadvantage is that the individual parts of this known downshift switch are subject to mechanical wear and thus subject to failure. The individual parts therefore cause additional inaccuracy.
A device for creating selector positions for use as a selector in an automobile on-board computer, in a washing machine control, or a gas pedal device is known from the International Patent Publication No. WO 98 26 341 A1, which is based on the German Patent Nos. DE 196 51 315 A1 and DE 297 14 164 U1. In the most simple embodiment of the selector switch, opposing magnetic units on a rotor are displaced from one position to the next, similar to the action of a mechanical detent mechanism. A position sensor unit is connected with the rotor that issues signals corresponding to each position. The rotor is rotatable about a tilt switch device. The tilt switch includes a tilt switch permanent magnet in a housing element secured to a magnetically.
For example, when the rotor is turned, a sensor may be selected in advance by the automobile on-board computer, and this pre-selection may be confirmed by subsequent pressure via the tilt switch. If the rotor is released after this pressure, the permanent magnet returns the rotor to its initial position.
Based on this state of the art, an object of the present invention is to better configure the downshift process and the creation of signals for an automobile automatic transmission.
Based on the invention, this object is achieved by using a tilting device with at least one movable magnet element as a downshift sensor device. When a pedal element causes actuation of a magnet element, a downshift characteristic curve (KL3) is generated with a curve-shaped increase and a maximum followed by a curve decrease (KLS) that ends in a stop window. A downshift point (KP) is determined using a tolerance window with a path width, which corresponds to a downshift signal (KS) on a characteristic motion curve (AS) of a motion sensor element.
The advantages provided by the invention particularly include the fact that a downshift magnetic force characteristic curve is created that may be correspondingly influenced based on the selection of magnetic forces of the magnets used. A further advantage is that the downshift point on this characteristic curve may be positioned beyond the maximum curve value within a tolerance window. A further advantage is that the downshift magnetic force characteristic curve is created using magnets, so that the mechanical parts are kept to a minimum, thus reducing the possibility of overall wear on the switch and allowing maintenance of smaller tolerances. With mechanical downshift switches, the curve maximum value is achieved after about 3 mm; with a magnetic switch, it is achieved after about 0.3 mm. Since the magnetic downshift switch does not have strict tolerance as is the case with mechanical switches, a good Gaussian distribution curve is achieved at the switching point.
The rising curve slope may be sinusoidal. It may, however, have another wave-like shape.
The curve drop may have a cotangential shape. It may also, however, have another wave-like shape.
The magnet counter-element may create a magnetic force progression, thus effectively determining the rising curve slope and the maximum curve value of the downshift magnetic force characteristic curve.
Additionally, a pressure spring element may be used that, along with the magnet counter-element, helps determine the curve rising slope of the downshift magnetic force characteristic curve.
A rotation angle sensor may be used as a motion sensor element. The sensor may operate according to the Hall principle. Thus, the most accurate motion characteristic curves may be used from which exact downshift signals may be taken. A rotary potentiometer could also be used here.
A Hall circuit may be used as the motion switch. It switches precisely at the downshift point, is equally exact, and is as free from external influences as the rotation angle sensor. An electrical switch could also be used as a motion switch that could provide a downshift signal upon actuation. This switch may operate according to mechanical, semi-conductor, or other principles.
The advantages connected with this device consist particularly from the fact that the use of magnetic elements to determine the progression of the downshift magnetic force characteristic curve reduces mechanical wear to a minimum. The characteristic curve may thus be significantly affected at critical points such as the rising slope, the maximum, and the falling slope. Instead of the fixed point using a mechanical switch, one may determine during actuation that the downshift point that creates the downshift signal lies beyond the maximum.
The repelling-magnet element may be disposed opposite the moveable magnet element on the one side, and opposite the plate element on the other side.
Thus, the moveable magnet element may be positioned with one pole opposite the same magnetic pole of the repelling-magnet element and with the other pole at least opposite the plate element. Thus, the curve progression may be very significantly influenced.
The curve progression of the characteristic force curve may be further influenced in that a pressure spring element is positioned between the plate element and the moveable magnet element. The pressure spring element may also be positioned between the moveable magnet element and the repelling-magnet element. The spring element may consist of rubber or spring steel.
The plate element may be made as a steel washer element.
The magnet element is to be moved by a pushrod element. Other elements may be used to move the magnet element.
The magnet element and the repelling-magnet element may be in the form of permanent magnets. The downshift magnetic force characteristic curve is effectively influenced by the selection of permanent magnets.
The magnet element and/or the repelling-magnet element may be divided into halves of a magnetic north and south pole, whereby the magnetic counterforce may be varied or increased. The magnetic counterforce and thereby also the downshift magnetic force characteristic curve may further be influenced if the magnet element is at least partially surrounded by an iron yoke.
Sensors that operate according to the Hall principle or the resistance principle may be used as a motion sensor element.
Switches that operate according to the Hall principle, a semi-conductor basis, or a mechanical basis may be used as a motion switch.
For a full understanding of the present invention, reference should now be made to the following detailed description of the preferred embodiments of the invention as illustrated in the accompanying drawings.